I recently had a private tour of Paramount Studios in Los Angeles. I was shown the famous stage where the original “King Kong” was filmed. “Do you know how big the real King Kong was?” The tour guide asked me. “He was huge!” I exclaimed.” “Wrong answer,” she said. “King Kong was an 18-inch puppet. Magnification and special effects did the rest.” Next we went into the prop room where a model submarine only a few feet long was hanging on a wall. “That’s the real Red October,” she said. The rest of the movie was filmed on a stage set. Then she showed me an ordinary parking lot. “Here is where we parted the Red Sea in ‘The Ten Commandments.’ ” A trench had been dug in the middle, and then the whole area was flooded with water. The film was edited and restitched backward so that the trench looked like it was emptying out. “Everything here is fake. That’s what you have to realize,” she said.

My tour guide did not mean “fake” in any negative sense. In the 20th century, such fake material was confined to the entertainment industry, which in that earlier age of technology was clearly separate from the news industry. Now the scope of what constitutes fake is vaster. And I do not mean President Trump’s false claims of “fake news,” which is merely news he doesn’t like or agree with. I mean the world of digital and video technology that has allowed the Hollywood mind-set of manipulating reality to distort how we think about the great issues of the day.

Objective, professional journalism — which seeks balance among respectable points of view — flourished, we should remind ourselves, within the context of the print-and-typewriter age: a more benign technology much less given to forgery and alteration compared with that of our current era. The digital-video age may have begun in the latter part of the 20th century, but we saw its dramatic effect on politics during the 2016 election. It is common for there to be a lag time between technological innovation and political-military effect. Recall that although the Second Industrial Revolution began in the mid-19th century, we did not really see its effect on war until 1914.

It is impossible to imagine Trump and his repeated big lies that go viral except in the digital-video age. It is impossible to imagine our present political polarization except in the age of the Internet, which drives people to sites of extreme views that validate their preexisting prejudices. And, in the spirit of Hollywood, it is impossible to imagine the degree and intensity of emotional and sensory manipulation, false rumors, exaggerations and character assassination that decay our public dialogue except in this new and terrifying age of technology which has only just begun.

Digital-video technology, precisely because it is given to manipulation, is inherently controlling. Think of how the great film directors of the 20th century were able to take over your mind for a few hours: a new experience for audiences that previous generations had never known. Theater may be as old as the ancient Greeks, but the technology of film lent a new and powerful force to the theatrical experience. Moreover, it was contained within a limited time period, and afterward you came back to the real world.

In the 21st century, dictators may have the capability to be the equivalent of film directors, and the show never stops. Indeed, Joseph Goebbels would undoubtedly thrive in today’s world. As for warfare itself, it will be increasingly about dividing and demoralizing enemy populations through disinformation campaigns whose techniques are still in their infancy.

The Chinese, eventually with the help of big data, are working on following the Internet searches of their citizens, and then determining who needs to be singled out for further observation. If a government or a company knows the destination and sequence of all of your searches, it is virtually inside your mind. The possibilities are frightening, and the vistas for oppression unbounded. The digital age, originally sold to us as empowering, could yet become the greatest threat to free thought and democracy in history. The very idea of something going viral is an expression of the mob more than of the individual. The fact that Google partially ranks search results in terms of how many other sites have linked to them reinforces groupthink, not individuality. The entire logic of the Web works toward popularity, not quality, and certainly not toward truth.

Never before have we had to fight for democracy and individual rights as now in this new and — in some sense — dark age of technology. We must realize that the fight for democracy is synonymous with the fight for objectivity, which lies at the core of professional journalism — a calling whose foundational spirit was forged in the print-and-typewriter age, when mainly the movies were fake.

We will fight best by thinking tragically to avoid tragedy. This means learning to think like the tyrants who feed and prosper on misinformation so we can keep several steps ahead of them. Only in that way can we build safeguards against the specific dangers of the digital experience. The pioneers of Silicon Valley were inherent optimists who simply believed in connecting the world. But it is precisely such integration that provides our authoritarian enemies with access into our own democratic systems. The future will be about wars of integration rather than wars of geographic separation. So now constructive pessimism is called for. The innocent days when illusions were the province of movie stage sets are way behind us.